1. Field of the Invention
The present invention relates to a video game apparatus for displaying in real-time a three-dimensional image on a display screen while the image varies depending on the position and direction of movement of a game character that moves on a water surface or the like displayed in a game space on the display screen according to operation of a manual controller, a method of displaying a plurality of models in the game space on the display screen of the video game apparatus, and a computer-readable recording medium which stores a program for controlling the video game apparatus.
2. Description of the Prior Art
There have been known driving video game apparatuses that are played by game players for simulating the driving of a vehicle, such as an automobile, on the display screen. One type of those driving video game apparatuses is played by the game player to manipulate a displayed game character to ride on a hydroplane thereby simulating the driving of the hydroplane on water.
Attempts have been made to give a realistic look to displayed images of such a video game apparatus by displaying reflections of nearby buildings, structures, and game characters on the displayed water surface. There have heretofore been available two major computer graphic techniques for displaying a water surface together with building, structure, and game character reflections thereon.
According to the first computer graphic technique, if a game character or a building is displayed as a dot-matrix image, then the dot-matrix image is vertically inverted or another dot-matrix image which is vertically inverted from the dot-matrix image is generated in advance, and is displayed over a displayed water surface.
According to the second computer graphic technique, if a game character or a building is displayed as polygons, a reflected image thereof is obtained by a mirror inversion process that carries out successive calculations to determine how those polygons are reflected on a displayed water surface.
The dot-matrix image displayed according to the first computer graphic technique is a two-dimensional image which represents a reflection on the displayed water surface from the position and direction of a certain fixed viewpoint. If the game character or the building is expressed three-dimensionally, then even when the dot-matrix image is accurately calculated, it is difficult to display it so as to follow the position of the viewpoint as the game character moves on the water surface.
The second computer graphic technique allows the reflected image to be accurately representative of the game character or the building that is displayed as polygons. However, since the successive calculations carried out by the mirror inversion process are time-consuming, the second computer graphic technique is not suitable for use with video games which are required to display images in realtime in quick response to manual operation by the game player.